There is some evidence to suggest that inoperable gliomas may respond to the direct intra-arterial infusion of certain chemotherapeutic agents. Agents currently used have significant ophthalmic toxicity when infused directly into the internal carotid artery. Selective perfusion of the chemotherapeutic agent beyond the carotid siphon would be preferable, but it is difficult to maneuver conventional catheters into this location, and spasm of the carotid artery induced by such large catheters is a significant hazard. We have been developing two microcatheters based upon the toposcopic principle and a retrograde pulsion principle for traversing tortuous vascular beds. Both catheters are undergoing extensive testing in animals and an IDE application from the FDA has been applied for in the cases of toposcopic catheter. When approved, both catheters will be selectively introduced through a conventional angiographic catheter, negotiated across the carotid siphon and positioned in the distal internal carotid artery or proximal middle cerebral branches for chemotherapeutic perfusion. Significance of Research: Since the last submission we have treated a group of patients with glioblastomas. Although technically successful in achieving good catheter position above the carotid siphon and extracoporeal perfusion of the jugular venous effluent, some cerebral toxicity did result from these high concentrations of chemotherapeutic agents. Further studies are underway to develop a pulsatile pump to overcome these problems of streaming.